Comprehensive performance evaluation of water and power production technologies using water-exergy nexus analysis

Abstract

Insight into less-known aspects of sustainable development has been deepened through the development of the nexus between water and energy in the last decades. However, the complex sustainability problem cannot be fully investigated owing to the intrinsic shortcomings of the physical concept of energy. This study considered the exergy concept as a substitute for energy to develop water-exergy nexus analysis (WExNa) as an efficient analytical framework. Accordingly, four evaluation criteria were proposed as quantitative tools of WExNa. Consequently, seven power and seven water production technologies were analyzed considering the model uncertainties in their life cycle. A big data bank, comprising 803 water and 812 power production plants, was labeled to facilitate consideration of the spatial, temporal, and environmental variety of technologies in a stochastic data-driven program. The results showed that wind, solar, and concentrating solar power plants used the least amount of water for exergy production during the entire life cycle, whereas only geothermal power technology could compete with non-renewable power in the operating stage by an exergy dissipation for product exergy index in the range of 0.2 – 3. Despite the significance of chemicals in water production, chemical exergy dissipation was negligible compared with electrical and thermal exergies. Water treatment facilities were generally superior to desalination technologies, considering all types of exergy for water. Although multi-stage flash and electrodialysis exhibited the best and worst operation metrics among the water technologies, they dissipated the most and least exergies for water production, respectively, with an acceptable confidence considering the entire life cycle. Moreover, the contrast between conventional operation indexes and the new WExNa variables entails potentially new horizons through the sustainable evaluation of engineering systems using the proposed analysis.